[Mesa-dev] [PATCH 3/5] nir: Do opt_algebraic in reverse order.

[Matt Turner]

On Sun, Feb 7, 2016 at 8:06 AM, Jason Ekstrand <jason at jlekstrand.net> wrote:
>
> On Feb 4, 2016 5:45 PM, "Matt Turner" <mattst88 at gmail.com> wrote:
>>
>> Walking the SSA definitions in order means that we consider the smallest
>> algebraic optimizations before larger optimizations. So if a smaller
>> rule is part of a larger rule, the smaller one will happen first,
>> preventing the larger one from happening.
>>
>> instructions in affected programs: 32721 -> 32611 (-0.34%)
>> helped: 106
>>
>> Prevents regressions and annoyances in the next commits.
>
> Mind doing just a little tooling to try and determine whether or not this
> increases the number of times the optimization loop runs?  Some
> Optimizations may immediately allow some other optimization on their result
> which will now have to wait until the next time through the loop.

In affected programs (129 of them):

before:  1164 optimization loops
after: 1071 optimization loops

Of the 129 affected, 16 programs' optimization loop counts increased.